A dielectric is an insulating material that does not conduct electrons easily and thus has the ability to store electrical energy when a potential difference exists across it. The stored energy is known as an electric potential or an electrostatic field which holds electrons. When the buildup of electrons becomes sufficiently large, the electric potential is discharged. Some common dielectric materials include glass, mica, mineral oil, paper, paraffin, polystyrene and porcelain. The effectiveness of a dielectric material is determined by its molecular constituents and its thickness.
In electronic circuits, dielectric materials are employed in capacitors and as circuit board substrates. High dielectric constant materials are used in radar or microwave applications and also for circuit miniaturization as the speed of propagation of signal at a constant frequency is proportional to the inverse of the square root of the dielectric constant of the medium through which it passes. Low dielectric constant materials are used for high speed, low loss transmission of signals as such materials allow faster signal propagation. Low dielectric materials also have radar and microwave applications. If the combination of materials is such that the loss tangent for a material of a given frequency signal is very low, the circuit board will allow very efficient transmission or splitting of the signal without electrical loss related to the hysteresis loop--(i.e. the graphical representation of by material field as a response to imposed alternating fields.) If a whole circuit were built on low dielectric material, one could amplify the signal only a certain amount at each mounted transistor because of the power involved which would build up excessive heat and temperature. Consequently, the amplification was spread over a large space. If all of the dielectric material had a high dielectric constant, there would be more loss at signal splits so that more transistors would be necessary to maintain a specific signal to noise ratio.
Because most applications require materials having a particular dielectric constant, there has been no need to juxtapose different types of dielectric material onto a common ground plane and overlain by a common conductor. Applicants have recognized that it would be particularly advantageous to have on one ground plane, materials of different dielectric constants, overlain by a common conductor, particularly if the different materials are to be used in conjunction with one another to take advantage of their differing properties.
It is accordingly an object of the present invention to create a MULTI-DIELECTRIC LAMINATE in which materials of different dielectric constants may be placed onto one common ground plane.
It is a further objective of the invention to obviate the necessity for a constant impedance device (a device which impedes current flow within an RLC circuit) and to eliminate the need for fastening separate ground planes, conductors and impedance devices onto a multi-dielectric laminate.
Another object of the invention is to shorten the time and expense required for printing, etching or wet processing onto separate conductor pieces of a multi-dielectric laminate.
Yet another object of the device is to increase the structural integrity and reliability of a multi-dielectric laminate.
Still another object of the invention is to create a multi-dielectric laminate on which the circuit lines may be printed and etched onto a common conductor across several types of dielectric materials to take advantage of their different properties.